This application is a 371 national filing claiming priority from international application PCT/EP2009/009143, filed Dec. 18, 2009. This application also claims priority from German application DE 10 2008 063 229.5, filed Dec. 19, 2008, and from European application EP 09 002 419.1, filed Feb. 20, 2009. The entire contents of that international application and that German application and that European application are incorporated herein by reference.
The object of the present invention is a felt material with a barrier function comprising at least one felt layer and an absorber containing material, as well as a method for the production of the felt material, a component made of this felt material and its use.
Felt is a fabric for textiles which has a sheet-like structure and which consists of mechanically bonded fibers. Unlike other fabrics, felt is not woven. Instead, it is manufactured under the influence exerted by pressure with the procedure for pressed felts, or by using an acid to roughen the fibers and to create a nonwoven fabric which is bonded by moisture and heat. Traditionally, pressed felts are made from wool or from other loose animal hair because due to the peeling structure of the hair, the fibers become mutually entangled. The hardness of the felt can range between that of soft cotton or of hard wood, and felts which have even a higher hardness can be also produced. The classical wool felts are also referred to as pressed or milling felts.
More recently, felts have been often produced as needle felts. In this case, the fibers are placed in layers on top of each other and processed with numerous needles which are provided with barbs so that they are pierced through several times. The repeated insertion of the fibers means that they are intertwined or pressed in the felt. The needle felts can be therefore manufactured not only from wool, but virtually from all known fibers.
Due to its warming properties, felt is used also for the manufacture of clothing, lining materials or shoes, as well as for insulating materials. They are particularly popular due to their warming effect, for example when used in shoes made of felts, or in felt hats or cardigans. In technology, felts are used for example for sealing materials made of felts, felt rings or felt strips, or as surface materials for sealing or soundproofing. In addition, technical molded parts or filters made from felt materials are also known. In addition to its heat insulating characteristics, felt is also permeable to air and to a certain extent it is waterproof. However, with a larger amount of water, for example when it rains, water will penetrate through the felt.
The felt material feels uncomfortable and heavy when it is wet because it traps water like a sponge.
In the area of sanitary pads or materials that are used for pillows, it is known that coating materials with super absorbent polymers can be used to absorb water and moisture. For example DE 698 33 007 T2 describes an absorbent product consisting of several layers which is equipped with an absorbent core for absorption of liquids. In order to protect clothing, one of the layers is in this case made from a plastic material, which means that the air permeability of the product is severely limited. The products used in this manner are in this case designed in such a way so as to achieve the maximum absorption of liquids. So far it has not been possible to control the distinct increase of weight and the increased volume of the product caused by this for application to hygienic articles. The large amounts of fluids thus result in correspondingly long drying time periods. In addition, the products are suitable only for single use and they must be disposed of once they have come into contact with fluids. Also, the products are not washable and the superabsorber would be separated from the carrier material as a result of mechanical influences such as during washing in a washing machine, or when it is compressed for a long time.
With respect to hygienic articles, it is further also known from DE 10 2007 016 959 that fiber sheets can be produced from cellulose fibers and that the absorption of these layers which contain cellulose fibers can be improved with the addition of a superabsorber. Also the products described in this document can be used only for disposable articles such as hygienic articles, medical products, diapers, panty liners, articles inserted in food packaging products or disposable filters. The described materials cannot be used in clothing articles or in areas in which repeated use would be required due to the small mechanical strength and also due to the high swelling displayed in case of contact with a fluid. As a result of the large amounts of fluid which are absorbed per surface area, these materials dry out only very slowly because a large volume of fluids must be evaporated. Moreover, the article is also quite heavy due to the large fluid absorption.